The primary goal of this project is to further characterize those factors influencing in vitro insulin and glucagon secretion from pancreas of normal and diabetic animals. Studies will include: 1. Role of calcium metabolism measured as Ca45 uptake and efflux on phasic insulin release from isolated islets. 2. Effect of Ca ions, sulfonylureas, energy inhibitors and other agents on the kinetics of insulin and glucagon release from the in vitro perfused pancreas. 3. Effect of continuous insulin and diet for prolonged periods on in vitro pancreatic function. Animals will include normal rats, streptozotocinized rats and the genetic non-obese diabetic Chinese hamster.